I'm having some trouble with the pivot mount installed on my Krieghoff Ulm Primus 9.3X74R double rifle at the time it was fitted with the double rifle barrels. As shown in this photo, the rings mate up perfectly with the bases, but when I try to fit the same scope to the same bases, I end up with about 1/16" gap separating the rear ring from the base. I feel as though I must be doing something wrong, but so far I have been unable to determine what it might be. Any suggestions?

Measure each ring to make sure they are the right size for the scope dia.

The make sure you have the proper rings front and back.

I had the wrong set for a Ruger no. 1 gave me all kinds of fits before I found out why

Just looking at your pic, the front mount looks way higher than the rear. At least you're mounting them on the same tube - I've got a bunch of s/h claw mounts here but ever getting them to match up for future use on the rifles I've got is a forlorn hope.

I feel as though I didn't describe my situation effectively: the scope and rings shown in the photo are those which were delivered with the rifle. Why they should fit perfectly in the rifle maker's shop and not with me installing it is what I can't understand. And they are not claw mounts.

In your picture, I cannot see the gap that you are describing. Ideally, the back ring should barely touch the base when you pivot the scope in line with the barrel, so the scope will not be distorted when you twist the locking ring. If indeed you have a significant gap, you could try turning the front ring around 180 degrees. If that does not improve the situation, you could either return the gun to whoever installed the bases, or you could lap the lower part of the front ring so the scope tilts a little bit further down.

Other pivot mounts have an adjustable front ring, so this would not be an issue.

JV: that's the correctly installed picture probably from the builder

I also wondered if the direction (from the left for from the right) mattered when turning in the scope. Im not sure how the rear base engages the rear mount so it's hard to say. Wouldn't think it would matter at all but something is clearly going on.

Sounds like a call to the builder is in order.

All the ones that I know are set up so one would hold the rifle in the left, the scope in the right hand and rotate the latter into position clockwise.

quote:

Originally posted by BaxterB:
JV: that's the correctly installed picture probably from the builder....
Sounds like a call to the builder is in order.

I have had extensive correspondence with the builder in Suhl, and his only suggestion has been to take it to someone in this country who understands such mounts.

AFAIK, the closest sources of such information are NECGS and Champlin Firearms, neither one very accessible to me in Tennessee.

So have you tried mounting the front ring the other way, i.e. turned 180 degrees?

Having trouble seeing how the rear base interfaces with the scope mount. Looks to be a MAK setup, but I thought those used a forward-tilt front scope ring that turned in, then sat/locked down into the rear base. This does not seem to work that way or am I missing it (clearly!)

When I call the mount a pivot mount, I mean that it is basically the same as the Redfield, Buehler, Leupold mounting systems: the front ring has a dovetailed protrusion which is fitted into an oblong opening in the base and the scope is then rotated (pivoted) 90 degrees until the rear ring lines up with the base.

The rotation is stopped by a flat projection on the right side of the bottom of the ring and locked in place with a hook projection which is then cammed down on the left side of the base by twisting the ring shown in the photo.

Well...they have a little something in common with the Leupold set up (If you drive by fast)

Lee Le Bas does a lot of these swing mounts, he's in Minden NV.

I'm not sure what you are saying.

Are you saying the rifle and scope were assembled and fit at the maker but now that you have it they don't fit?

Or, are you saying the rings were fit and now that you install a scope they do not fit?

Did you take the picture above? It looks like the scope is fully seated. Am I wrong?

The separation at the rear, is that the ring ending up 1/16" too far back or is it side-to-side? I notice that the rear ring is butted up against the turret housing and it looks like it has a mark from sliding into the housing. If the gap is front to rear perhaps the scope wasn't fully secure in the rings and got knocked back, at least that's what the picture suggests to me.

quote:

Originally posted by xausa:
When I call the mount a pivot mount, I mean that it is basically the same as the Redfield, Buehler, Leupold mounting systems: the front ring has a dovetailed protrusion which is fitted into an oblong opening in the base and the scope is then rotated (pivoted) 90 degrees until the rear ring lines up with the base.

The rotation is stopped by a flat projection on the right side of the bottom of the ring and locked in place with a hook projection which is then cammed down on the left side of the base by twisting the ring shown in the photo.

Got it, thank you.

On the pivot mounts that I am familiar with the front ring is multiple pieces held together by cap screws. Some are just screwed together others are a dovetail and screw affair.

Could it be the dovetail section of your front ring is loose or has shifted when the scope was pivoted off? It could just need to be taken apart, aligned and tightened up with some locktite.

Without more photos it is really hard to tell which mount you have, and what the issue could be.

Just a thought. Hope you get it worked out, that is a neat rifle.

Jeremy

quote:

Originally posted by Grenadier:
I'm not sure what you are saying.

Are you saying the rifle and scope were assembled and fit at the maker but now that you have it they don't fit?


Did you take the picture above? It looks like the scope is fully seated. Am I wrong?

The separation at the rear, is that the ring ending up 1/16" too far back or is it side-to-side? I notice that the rear ring is butted up against the turret housing and it looks like it has a mark from sliding into the housing. If the gap is front to rear perhaps the scope wasn't fully secure in the rings and got knocked back, at least that's what the picture suggests to me.

The pohoto above was taken by the maker in Suhl using my scope. I have changed nothing on the scope.

The gap is vertical. The rear ring does not sit down on the rear base and cannot be forced down. For that reason, the rear ring locking device does not engage the base, locking the scope in place laterally.

This is not the answer you want, but I had the same issue with a drilling and ended up having to use a Recknagel ring on the rear with an EAW ring on the front.

Sorry, I must confess that I can´t understand the description where the problem is.
If you need(want) to force down the rear base because the ring does not sit down you must have a horizontal gap. That sounds that the height of the rear foot is not correct.(Easy to cure).
Where is the vertical gap ?

Here is a photo to illustrate the problem:

Interesting. have the rings been taken off the scope since the original pic was taken? Looks like some adjustment has been made based on the turret/ring locations. If they have been taken off, is it possible the front ring was flipped? Meaning that it was fitted having a "front and rear" and the ring needs to be turned 180 and reinstalled on scope? Dunno, just guessing. This is an odd problem for sure.

In looking st the top pic again, the tops of the bases are different heights, so maybe to compensate for this and fitting s system that wasn't made specifically for these barrels, he angled the bottom of the ring (as opposed to the base) to get the rear to sit down on the rear base. If you install the rings with the scope loose, does the scope sit nice and flat in the bottom of the rings?

Well, I hate to let logic prevail. But if the rings are the right height to the line of bore. And the scope is sitting to high in the back. There can be only one of two options. First, the vertical alignment between the bore line and the ring is off (The ring is leaning forward). That causes the scope to be riding down hill to the bore line causing the back to be high. Secondly the horizontal surface on the bottom of the front ring is not square to the bore line. It would be machined running down hill to the bore line which again lifts the back of the scope up when the ring is tightened.

If one were to drop the scope into the rings and run all the screws in finger tight by hand and then tighten them with a screw driver, the problem probably wouldn't become evident. But if one dropped the scope in and fully tightened the front ring, then the back end of the scope would jump up, leaving a gap like you see.

But without actually seeing it it's just shooting in the dark. I'm surprised that the master gunsmith whose working on it can't ascertain the problem, but in this world of boutique specialists I suppose it's just the way of things today.

Zero the scope, put a bore sighter on it with the scope held tightened only in the front ring and it will tell you if the scope is parallel in the front ring. If it won't come to zero in that configuration put both rings on without the tops and lay the scope in and retry the bore sighter. If it will suddenly bore site like that then it's not a height problem, it's an out of square problem.

If it is an out of square you can probably cure it by just lapping in the lower halves of the rings.

If you do the math. The front ring would only have to be out of square less than .025 inch to lift the rear of the scope .100 inch to high. You have a tapered rib, soldered to a tapered barrel, with a dove tail milled into it, with a dove tail blank driven into it, which has a rotary dove tail milled into it, with a corresponding rotary dove tail forced into it and this was all done by a Bavarian Gunderspeil with marriage problems who just got back from a 4 beer lunch! Shit happens!

I see the rear ring and the turret are not in the same relationship between the two photos...I'd tend to jump to a conclusion of improper assembly after it left Europe

Yeah it looks pretty funky Duane. It also looks like the scope is running down hill to the rib on the barrel. But it could be that he was too close when he took the photo and it's fish-eyed. Also who knows if the rib is not running uphill to the bore lines. Hard numbers are the only thing that will prove anything. Someone has to sit down with a micrometer and or a collimator to find out what's going on. But I'm gonna bet my money that the rings are parallel but front ring is out of square and is pushing the front end of the scope down somehow.

For me the bottom of the locking ring and the top of the rib ( at least the part slotted in the rib) running parallel.
Therefore I guess that the scope and boreline are correctly fitted.
The correct height is achieved by the correct height of the spacer ring (the part between the scope ring and the locking ring).
That part is always individually fitted on a lathe.
If it was ever correct it must have been mingled with the wrong parts.
Loose the screw on the bottom of the locking ring, Fasten the locking ring on the prism and measure the needed height difference between the top of the locking ring and the underside of the scope ring when turned in the correct position .Mail the needed dimensions to your smith in Suhl.

quote:

Originally posted by xausa:
I feel as though I didn't describe my situation effectively: the scope and rings shown in the photo are those which were delivered with the rifle. Why they should fit perfectly in the rifle maker's shop and not with me installing it is what I can't understand. And they are not claw mounts.

No, xausa, I did not think yours were claw mounts - but I can't understand why are you asking here when you have probably paid a small fortune to the makers to have the scope mounted. Surely they should nominate an American agent to sort out the problem or get you to send the rifle back. In days of yore they would have been expected to mount the scope to near zero without recourse to the knobs, regulating the barrels to account for the extra weight if necessary.

Admittedly, they would have been working with a steel scope tube or a stout dural one with a rail to stiffen it and take any strain from poor alignment - not quite the case with the scope I see in your picture.

Despite the prices and reputation of certain makers, they do not always send their double rifles out perfectly set up. I bought one from the best German maker I knew of. It arrived fully assembled in a long case. After I had taken it to pieces to put in a shorter case, the fore end was too tight to go back on. On my notifying the maker, the dealer who'd brought it into the country for me came and got the rifle from my house, had it repaired and brought it back - by then it fitted perfectly.

Perhaps lifting too hard on the back of the scope while removing or installing it caused the problem. If it was mine I'd swing the scope to the side and force it down a bit to see if that "fixes" it. Of course, I'm not a gunsmith but it seems to me that a robust swing out system and a decent scope would be able to take a little tweek like that. If the distance between the center lines of the rings is 4" then we're talking about a rotational tweek of less than a degree. Once the scope is locked in, well, it's locked in.

Go ahead, start throwing stuff at me, I'm waiting for it. But I've had to tweek some pretty high tech stuff in my day to get it to fit and/or function.

Yes, Grenadier, that might be the only way to go if the installer does not come to the party. At least that Leupold appears to have a 30mm barrel. People debate the meaning of the thicker tube but in the European ones I think part of it is to allow thicker walls for more strength.

I would like to thank everyone for his contribution. I tried Grenadier's suggestion with no success. I think I have answered my question which was "Was I overlooking something obvious in trying to get the parts to mate up again."

The ring/scope combination has not been disturbed while in my possession. It appears that the scope was readjusted slightly to the front, I assume during the sighting in process, at some time after the initial photo was taken, but that was the way I received it.

I am planning a trip to the Northeast later on this year and I will see if Mark Cromwell at NECGS can put things right. Torsten Retz (Retz und Sohn, Suhl) who did the work for me originally has other projects of mine in the works and if I end up paying anything substantial, I am sure we can arrive at an amicable financial solution, based on the payment still due him.

Among the projects he has in his shop are a Jaeger/Simson drilling and a Nimrod drilling. He is fitting a new bundle of barrels for the former and a new rifle barrel for the latter. Since he is also building Nimrod drillings and double weapons from scratch, I consider him over qualified for those jobs. http://www.retzandson.com/

Good luck with getting it all sorted out. I'd be interested to see the solution to this.